1. Field of the Invention
This invention relates to a plastic cover for a metal container and, more particularly, to a plastic cover which is removable from the metal container to allow the plastic cover and the metal container to be separately recycled. The cover is especially suited for aerosol cans.
2. Prior Art
A typical aerosol can has a plastic cover which is attached at the upper face of a metal container. The container holds its contents under pressure and the cover has a nozzle which allows the user to release the contents from the container. The cover is usually firmly attached to the container by the interaction between a lip on the cover and a top lip or curl of the container. Because of the tight lock between the lip of the cover and the curl of the container, the two are recycled together, rather than separately. Because the container and cover are made of different materials, there is a need to separate the two for efficient recycling.
One suggestion for making the cover easily removable from the container is suggested in Japanese Patent Application No. 9-52584. The teachings of the '584 application are illustrated in FIGS. 6A-6C. As shown in FIGS. 6A-6C, cover 7 is attached to container 8. Cover 7 has nozzle 71 and inner cylinder 72 with an opening or discontinuous portion 72'. Attached to inner cylinder 72 is lip 73, which is shown as two sections. Each section has two circumferential ends 74 and a side portion 74'. Lip 73 is uniform in dimensions throughout, i.e. from circumferential end to circumferential end. Outer cylinder 75 has press point 76 which is used to deform cover 7 into an elliptical shape as shown in FIG. 6C. When cover 7 is deformed into this elliptical shape, cover 7 can be removed from container 8. Conventionally, cover 7 is molded from a plastic material into one piece and container 8 is made of metal.
Metal container 8 has a sloping wall section 81, curl 82 and stem 83. Stem 83 along with the other structure, not shown, allows for the contents of container 8 to be jetted out of container 8. Curl 82 interacts with lip 73 to hold cover 7 onto container 8 in a conventional way. Stem 83 fits through nozzle 71 as shown in FIG. 6A.
To assemble cover 7 on container 8, cover 7 is pushed down onto container 8 and lip 73 forces inner cylinder 72 to flex outward while lip 73 rides over curl 82. Lip 73 then locks into the concave portion under curl 82 and holds cover 7 onto container 8.
To remove cover 7 from container 8, the user pushes on press point 76 to force cover 7 into an elliptical shape as shown in FIG. 6C. A gap forms between curl 82 and side portion 74' of lip 74 and cover 7 can be removed from container 8.
Although the arrangement in FIGS. 6A-6C allows cover 7 to be removed from container 8, there is a need to improve this arrangement and make it easier to separate the two components, cover 7 and container 8.